The present invention relates to a cross-member for being connected to two longitudinal frame beams of a vehicle, i.e. frame beams positioned along the length of the vehicle, which cross-member also provides for a less complex and improved way of mounting components to the frame beam.
The mounting process of components to a vehicle chassis can be categorized into two main procedures, pre-assembly and final assembly. During pre-assembly, individual components are mounted together as modules, while final assembly represents the final mounting step where individual components or pre-assembled modules (units) are positioned at the correct position on the vehicle frame structure and thereafter mounted to the frame by fixing elements. Many types of mounting techniques are used in the automotive industry for fastening components to the chassis (frame structure) of a vehicle. Mounting generally includes the use of fixing elements, such as screws, rivets and/or bolts which connects the component to the frame beam.
In U.S. 2009/0302179, a holding device for fastening an add-on part to the frame structure of a vehicle is described. The holding device is fastened to an outer side of the frame structure. The holding device comprises a hook for fastening an add-on part to the frame structure, and the add-on part has a complementary shaped fixing surface so that a positive locking connection is formed between the holding device and the component.
It is in the interest for the vehicle industry to find improved ways of mounting components and modules to the chassis in order to find less costly and more ergonomic mounting methods. When mounting a component to a frame beam of a heavy vehicle there is often also a focus on achieving a connection between the component and the vehicle which has improved robustness.
It is desirable to find an improved way of mounting components to the frame structure with improved results in terms of increased robustness, improved ergonomics during mounting and maintenance, less complexity, and less mounting costs. In particular, it is desirable to find an improved way of mounting wheel suspension components to a vehicle frame structure and at the same time to achieve a more stable wheel axle construction.
According to an aspect of the invention, a vehicle having a frame structure comprising two longitudinal beams connected by a cross-member comprising a main portion and two end-sections wherein each end section comprises an outer surface for facing an inner surface of a longitudinal frame beam wherein the cross-member comprises at least one protrusion extending from the outer surface of the end-sections for being introduced into a hole or notch of the frame beam for forming a form-lock to one or more components to be mounted to the longitudinal frame beam.
The cross-member allows for that a more stable construction is achieved since the form-lock provides a tight connection with low tolerance distances and high connection area between the component and the cross-member. Further, the construction is stabilized since the outer surf of the cross-member is aligned to the inner surface of the frame beams. This results in a more stable connection of a component to the frame beam than adding a connection member to the outer surface of the frame beam for mounting the component.
Furthermore, by the form-lock and its position on the outer side of the end-sections of the cross-member, the cross-member can also provide direct mechanical support to the component to be attached. For example, this is important for large modules (units) to be mounted to both sides of the frame, such as a wheel axle suspension module.
In addition, by using the cross-member, the mounting procedure of the component is made less complex since the exact positioning of the component on the chassis becomes easier to find due to the protrusions of the cross-member extending on the outside of the frame beam, fewer fixing elements are needed, and due to the additional stability achieved by the cross-member, mounting steps can be moved from final assembly to pre-assembly procedure. For example, for a wheel axle suspension module, wheel alignment can be done already during a pre-assembly procedure. In addition, improved ergonomics for the worker is achieved as the form-lock created by the protrusion and the complementary recess makes it easy to assemble modules or complete units instead of mounting separate components. Also, the possibility to form-lock components directly to the protrusions on the cross-member reduces the amount of other types of fixing elements needed.
In embodiments of the invention, an outer portion of the protrusion is adapted for locking the component upwards and/or downwards relative a height direction of the vehicle. Thereby, the component can be significantly stabilized in vertical direction of the vehicle since any vertical forces to which the component is exposed will be directly distributed to the cross-member.
In embodiments of the invention, an outer portion of the protrusion is adapted for locking the component relative the length direction of the longitudinal frame beam. Thereby, the component can be significantly stabilized in length direction of the vehicle since any longitudinal forces to which the component is exposed will be directly distributed to the cross-member.
In embodiments of the invention, an outer portion of the protrusion is adapted for locking the component rotationally (R) relative a direction along the frame beams. This can be achieved for example by using at least one protrusion which outer portion has a non-circular cross-sectional area or by using at least two circular protrusions at each outer surface of the cross-member facing the inner surface of the frame beams. This is an efficient way of creating improved stability of a component to be mounted to a frame structure since the cross-member will support the component as an integrated part of the component.
In embodiments of the invention, an outer portion of the protrusion is adapted for locking the component in transverse direction relative the length direction of the longitudinal frame beam. The locking mechanism ensures a more exact positioning in transverse direction compared to the use of traditional fixing elements such as screws, rivets and bolts. When using screws, rivets and bolts the exact positioning is dependent on the worker mounting the component, while when using the form-lock, the component can be positioned more exactly in transverse direction. This combined with the direct connection to the cross-member results in a significantly increased robustness in transverse direction.
In embodiments of the invention, an inner portion of the protrusion is arranged to form a form-lock to the frame beam. Thereby, a form-lock between the frame and the cross-member is created in addition to the form-lock between the cross-member and the component. The cross-member will hence be fastened with increased robustness to the frame structure compared to attachment with only screws or bolts. Hence, the component will form an integrated unit with both the cross-member and the frame beams. Thereby, a high stability is achieved which is advantageous for components with high load impacts, for example a wheel axle suspension module. In other words, the protrusions are positioned on the frame structure with increased precision so that the resulting connection between the component and the protrusion can be superior compared to for example using a form-fit holder mounted to the outside of the frame by traditional fixing means. In order to obtain a similar locking function of the frame beam, the outer surface may alternatively comprise one or more additional protrusions, wherein the additional protrusions are arranged to form a form-lock between the cross-member and the frame beam.
In embodiments of the invention, the main portion of the cross-member comprises connection points for mounting additional functional components. Thereby, efficient mounting of components, such as a wheel axle suspension module may be achieved.
According to a second aspect of the invention, a vehicle comprises a cross-member as described above, wherein the cross-member is arranged between two longitudinal frame beams of the vehicle and the at least one protrusion extends through a longitudinal frame beam and forms a form-lock to the component, wherein the component comprises at least one recess with complementary shape compared to at least an outer portion of the at least one protrusion. As described above, such cross-member provides several advantages when used in a vehicle, in terms of higher stability of components mounted to frame using the cross-member as connector, less costly construction due to that the possibilities to use a less complex mounting process with fewer mounting steps in the final-assembly mounting procedure.
In embodiments of the invention, the component comprises additional connection points, for example threaded holes, for fixing the component (or module) to the protrusion, and/or to the frame beam. Thereby, the component may be fastened in the remaining directions where the protrusion does not form a lock. For example, in the case of mounting from the top, the component may be additionally fastened by fixing elements attached at the top of the protrusion. Also the component can be additionally fastened to the frame beam by traditional fixing elements.
In embodiments of the invention, the component to be connected to the frame beams is a driven or non-driven wheel suspension unit. It may be a rigid axle unit or an individual wheel suspension unit. For example, the wheel suspension unit may comprise at least two suspension brackets, which each comprise at least one recess with complementary shape compared to at least the outer portion of the protrusion for forming a form-lock to the cross-member and/or to the frame beams. Using the cross-member of the invention for mounting a wheel suspension module allows for a significant improvements during the mounting process as the exact position of the wheel assembly module allows for that the wheel alignment can be done as a pre-assemble mounting step. Today, the wheel assembly is first mounted to the frame and wheel alignment is done in the final assembly to the chassis. Further, the final assembly is made less complex as the form-lock allows for the use of less other fixing elements in the narrow space available in the chassis.
Furthermore, a significantly more stable construction is achieved due to the direct mechanical support of the cross-member and/or the frame beams created by the protrusions, which at least partly integrates the cross-member into the wheel suspension arrangement. For example, in the case of the use of an individual wheel suspension, the longitudinal frame beams of the vehicle can be exposed to rotational forces in transverse direction during travel. The direct connection to the cross-member via the form-locking protrusions at the two longitudinal frame beam results in an efficient stabilization of the frame beams in transverse direction. In contrast, today extra support structures are used in order to mitigate instability effects of such transverse rotational forces.
In embodiments of the invention, a height between an upper and lower surface of the end-sections may be smaller than the height of the cross-member. This allows for that cables and piping can be mounted along the inner side of the frame beam efficiently.
According to a third aspect of the invention, a method for mounting a component to a longitudinal frame beam of a vehicle comprises the steps of:
a) providing a cross-member according to the invention,
b) providing a component having a recess which has an essentially complementary shape compared to at least an outer portion of the at least one protrusion;
c) inserting the at least one protrusion into a hole or notch of a frame beam so that at least an outer portion of the protrusion extends through the hole or notch and at an outer surface of the frame beam; and
d) attaching the component to the frame beam by allowing the protrusion to be received in the recess of the component for forming a form-lock to the component.
The advantages of the method is that modular mounting is facilitated so that less mounting steps are needed in the final assemble, increased ergonomics, less complexity and reduced costs as explained above.